It seems to have settled, its hard to tell whether his going to the toilet though now that Milo is here, my biggest worry is his bladder getting blocked. Jess has only really ever wee'ed around twice a day, and this morning there was lots of wee in the downstairs litter tray so I'm assuming they had both been over night.
We've got the Cystease from the vets 100 tabs for £26 but in future I'll order them though work (I work for Dogs Trust, so our vet can order them for me)